With my last Dominate He wanted to have multiple subs. However, imho, He did not approach it the correct way, at least not for me.

He structure concept was one of having a female slave, fully trained, and adding a female sub who was a switch... a sub to Him a Domme to the slave into the mix after training the slave.

Overall in theory that sounded like a reasonable plan. Several problems arose though in that He was not up front about that plan in the start of the relationship, expected the slave to help in the search for the switch sub, expected both to be bi (which one was not interested in at all) and barely had time for one and yet still wanted a second.

Luckily it never came to full fruition while i was with Him... and wouldn't have from my point of view. Although it did put a huge strain on the relationship, destroyed the trust, and left an overall bad impression.

So... imho, it probably can work, a Dom having multiply subs but it requires a very special set of people to make it all work, up front honesty, and a lot of negotiation, planing, etc.